A reactor is one of parts in a circuit that performs a step-up operation and a step-down operation of voltage. For example, PTL 1 discloses a reactor that is used for a converter mounted on a vehicle such as a hybrid electric vehicle. The reactor includes a coil, a ring-shaped magnetic core at which the coil is arranged, a case that houses an assembly of the coil and the magnetic core, and sealing resin with which the case is filled. The reactor is generally fixed to a fixing object such as a cooling base, and is used for cooling the coil etc., which generates heat while being energized.
The case is typically a die-cast product of aluminum. The case is fixed to the cooling base and is used as a heat-release path for the heat of the coil etc.